The invention relates to a top entry ball valve. Top entry ball valves are well known in the art. Such valves are constructed to allow removal and replacement of the valve element without removing the valve body from the pipeline in which the valve is installed. Since top entry ball valves do not have bolts which hold the end caps of the valve together and which apply a compressive force to the valve seats to create a leak-proof valve, wedge-shaped elements located on either side of the ball which are in contact with the valve seats are utilized to provide the necessary compression. Such a construction is shown in U.S. Pat. No. 3,838,844. The interior surface of the valve casing against which the wedge-shaped element bears is a flat machined surface formed by an expensive manufacturing technique referred to as back spot facing. Back spot facing requires that a tool be inserted into a valve casing from one of the valve inlets and thereafter expanded and backed up in order to perform the facing operation. Two such faces must be formed in each valve and since these faces should be parallel within a few thousandths tolerance, the back spot facing operation requires precision tooling and a substantial amount of time to perform properly. Such expensive machining and time-consuming techniques result in a valve which is costly and difficult to manufacture. It would, therefore, be advantageous to provide a top entry ball valve which does not require internal parallel flat surfaces formed by a back spot facing operation.